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1. Ceramics Industry
RABIA AZIZ
BS-III Chemistry
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2. Introduction:
 CERAMICS The word ceramic is derived from
the word (keramikos).
 "Ceramics" means articles and objects made of
clay with definite/permanent shape and fired at
high temperatures.
 They are Inorganic and nonmetallic solids.
 The two most common chemical bonds for
ceramic materials are covalent and ionic.
 Most ceramics are thermal and electrical
insulators.
 The best-known ceramics are pottery, glass,
brick, porcelain, and cement.
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6. Raw Material:
 Clay
 Bauxite
 Feldspar
 Quartz
 Grog (broken ceramics use → recycle)
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7.  Purpose: Clay is the only one and the
unique material which when
moistened with a suitable quantity of
water, develops "PLASTICITY" which
helps in manufacturing unlimited
number of objects in various shapes
and sizes.
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8. Classification:
1. White wares
2. Porcelain enamel
3. Structural clay products
4. Refractories
5. Abrasives
6. Special ceramics
7. Pure oxide ceramics
8. Nuclear ceramics
9. Electro-optic ceramic
10. Magnetic ceramic
11. Ceramic nitrides
12. Metal-ceramic composites
13. Ceramic borides
14. Ferro-electric ceramics
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9. Manufacture Process:
 Ceramics are generally made by taking
mixtures of clay, earthen elements, powders,
and water and shaping them into desired
forms. Once the ceramic has been shaped, it
is fired in a high temperature oven known as
a kiln. Often, ceramics are covered in
decorative, waterproof, paint-like substances
known as glazes.
 Raw material → Crusher → Mixer → Filter press
→ Pug mill (mixing machine) → Dryer → Glazing
→ Kiln → Finishing → Quality check → product
for packing dispatch
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10. Detail:
 Raw material are procured, crushed and
mixed
 Making paste: Crushed raw material blunged
in blungers to prepare slurry, either use for
moulding or passed through filter press for
dewatering which is further proceed before
molding.
 Moulded in shape
• Moulding: Dry or wet →mostly
• Dry Moulding: Crushed raw material +
binders → press moulding.
 Dried in open or heated chambers
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11. Dip or spray glazed, drying and fired in
kiln 900°.
or
Fired in kiln. This firing called biscuit firing
and then glaze, dried and re-fired.
Finishing operation: manually or
mechanically
Final firing in the kiln
Cooling and unloading the kiln
Inspected for quality check
Product is ready for dispatch.
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12. Types of Kiln: depends upon types of
product, fuel available and
temperature.
 Down draft kiln
 Chamber kiln
 Tunnel kiln
 Top hat kiln
 Vertical shaft kiln
 Tank furnace
 Shuttle kiln
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13. Down draft kiln
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14. Chamber kiln
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15. Tunnel kiln
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16. Top hat kiln
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17. Vertical shaft kiln
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18. Tank furnace
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19. Shuttle kiln
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20. Stages During Firing:
 Dehydration: (150-600°C) By Dehydration,
Mechanical water and chemical combined water is
removed.
• Mechanical Dehydration(water smoking)
• Chemical Dehydration(chemical water smoking)
 Oxidation: (300-950°C)
• Oxidizable Sulphur and carbor are removed
• Ferrous ions → ferric ion
• Ca and Mg carbonates dissociate into their respective oxide
and Carbon dioxide.
 Vitrification: The period during which some of minerals
melt to a glassy state and on cooling bond the unmelted
particles into a film mass.
 The progressive reduction in porosity is called
vitrification.
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21. Coloration: Color glaze by chemicals
or minerals
 Minerals: MgO, chrome ore/ Chrome
oxide, Mn & its compounds, Pb
compounds, Zn compounds, Na
compounds, Ba compounds, titanium
compounds, borax.
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22. Industrial Methods
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23. Industrial Methods
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24.  The two main categories of ceramics: are
traditional and advanced.
 Traditional ceramics include objects made of clay
and cements that have been hardened by
heating at high temperatures. Traditional
ceramics are used in dishes, crockery,
flowerpots, and roof and wall tiles.
 Advanced ceramics include carbides, such as
silicon carbide, SiC; oxides, such as aluminum
oxide, Al 2 O 3 ; nitrides, such as silicon nitride, Si
3 N 4 ; and many other materials, including the
mixed oxide ceramics that can act as
superconductors. Advanced ceramics require
modern processing techniques, and the
development of these techniques has led to
advances in medicine and engineering.
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25.  Types of clay and their common ceramic uses: Six
types of clay : common clay, kaolin (China clay),
bentonite, ball clay, fuller's Earth, and fire clay, and each
has a number of different uses:
 Common clay is mostly used for bricks, cement, and
aggregate.
 Kaolin is widely used for making glossy paper.
 Bentonite has a variety of industrial uses, including
drilling mud and foundary sand, and is also found in
household products that absorb pet waste.
 Ball clay is a high quality clay prized for its use in
ceramics, sanitaryware, and wall and floor tiles.
 Fuller's Earth is also used for pet-waste products.
 Fire clay is used in refractory (high-temperature) bricks
and cement.
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26. Properties of Ceramics:
Most ceramics are hard, chemically
inert, brittle, refractory (can withstand
very high heat without deformation),
and poor conductors of heat and
electricity.
Ceramics also have low densities.
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27. Terms
 Efflorescence: Also called whitewash,
drier white, kiln white, wall white,
sulphation, and scumming, refers to
discoloration on the surface of clay
products due to soluble salts in the clay.
 Spalling: a fracturing of arefactory
brick, due to uneven heat stress or
compression caused by heat is kown as
spalling.
• bricks (or other refractory ware) + heat →
expansion or contraction (stress between
parts) → pieces of the bricks break off.
• This breaking off called spalling.
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28. Uses of Ceramics:
Ceramics are used as refractories in
furnaces and as durable building
materials (in the form of bricks, tiles,
cinder blocks, and other hard, strong
solids).
They are also used as common
electrical and thermal insulators in the
manufacture of spark plugs, telephone
poles, electronic devices, and the
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29. Type of Ceramic
Refractories: use in fire work
 Physical Properties: Porosity, spalling, strength
 Chemical Properties:
i. Acidic → silica bricks
ii. Basic →magnesite bricks
iii. Neutral → fire-clay bricks
• High alumina composition → bauxite, diaspora (Al ores)
 Manufacture:
1. Grinding
2. Mixing
3. Molding
4. Drying
5. Burning
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30. CONCLUSION:
 Ceramics can be defined as heat-
resistant, nonmetallic, inorganic solids
that are (generally) made up of
compounds formed from metallic and
nonmetallic elements. Although different
types of ceramics can have very different
properties, in general ceramics are
corrosion-resistant and hard, but brittle.
Most ceramics are also good insulators
and can withstand high temperatures.
These properties have led to their use in
virtually every aspect of modern life.
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